Learning to tune the antero-posterior propulsive forces during walking: a necessary skill for mastering upright locomotion in toddlers
- 211 Downloads
This study examines the process of learning to walk from a functional perspective. To move forward, one must generate and control propulsive forces. To achieve this, it is necessary to create and tune a distance between the centre of mass (CoM) and the centre of pressure (CoP) along the antero-posterior axis. We hypothesize that learning to walk consists of learning how to calibrate these self-generated propulsive forces to control such distance. We investigated this question with six infants (three girls and three boys) who we followed up weekly for the first 8 weeks after the onset of walking and then biweekly until they reached 14–16 weeks of walking experience. The infants’ walking patterns (kinematics and propelling forces) were captured via synched motion analysis and force plate. The results show that the distance between the CoM and the CoP along the antero-posterior axis increased rapidly during the first months of learning to walk and that this increase was correlated with an increase in velocity. The initial small values of (CoM–CoP) observed at walking onset, coupled with small velocity are interpreted as the solution infants adopted to satisfy a compromise between the need to generate propulsive forces to move forward while simultaneously controlling the disequilibrium resulting from creating a with distance between the CoM and CoP.
KeywordsWalking Learning Propulsive forces Centre of pressure Centre of mass Longitudinal study Lower limb kinematics
We would like to thank the parents and their infants for their enthusiastic participation in this study. This work could not have been accomplished without them. Data collection was performed while Blandine Bril was on sabbatical at Purdue University, West Lafayette, USA. We thank Dr. Shirley Rietdyk for giving us access to her biomechanical laboratory and recording equipment. Preliminary analyses of these data have been presented at The International Conference SKILLS 2011 in Montpellier and published in the proceedings of the conference Dupuy L, Bril, B, Dietrich, G, Corbetta, D. (2011) A functional approach to learning to walk: preliminary results, BIO Web of Conferences 1, 00021 (2011). doi: 10.1051/bioconf/20110100021.
- Bernstein N (1967) The coordination and regulation of movements. Pergamon Press, LondonGoogle Scholar
- Bril B, Smaers J, Steele J, Rein R, Nonaka T, Dietrich G et al (2012) Functional mastery of percussive technology in nut-cracking and stone-flaking actions: experimental comparison and implications for the evolution of the human brain. Philos Trans R Soc Lond B Biol Sci 367(1585):59–74PubMedCentralCrossRefPubMedGoogle Scholar
- Jian Y, Winter DA, Ishac MG, Gilchrist L (1993) Trajectory of the body COG and COP during initiation and termination of gait. Gait Posture 1(9):22Google Scholar
- Sutherland DH, Olsen R, Biden EN, Wyatt MP (1988) The development of mature walking. Mac Keith Press, LondonGoogle Scholar
- Winter DA, Eng P (1995) Human balance and posture control during standing and walking. Gait Posture 3:193–214Google Scholar
- Zatsiorsky VZ (1998) Kinematics of human motion. Human Kinetics, ChampaignGoogle Scholar